Aircraft must balance the need for operational payloads, or devices, with flight efficiency requirements including weight, drag and maneuverability requirements. Certain operational payloads such as weapons, sensors and cameras are typically mounted on the underside of the aircraft fuselage to maintain a clear line of sight to their intended target. Such operational payloads are often rotatable about one or more axes to allow for targeting of specific elements in the air or on the ground. One common type of exterior rotatable payload is a gun turret mounted on the underside of an aircraft's fuselage. Gun turrets typically house a weapon, and sometimes a crew member, while being capable of some degree of azimuth and elevation, or cone of fire, through which the weapon may be aimed and fired. Another type of exterior rotatable payload is a gimballed sensor turret that hangs from the underside of an aircraft's fuselage and employs sensors to perform airborne observation, surveillance or reconnaissance.
One reason why such exterior rotatable payloads are mounted on the underside of the fuselage is because the fuselage underside presents a horizontal surface, which provides an orthogonal and predictable load and center of gravity and sometimes helps to reduce moments on the airframe of the aircraft. Undermounted external payloads, however, do not take advantage of the improved structural strength of modern aircraft airframes and also increase the forward-facing profile of the aircraft, thereby increasing drag and reducing aircraft efficiency. Accordingly, a need has arisen for turret systems that allow rotatable operational payloads to be mounted to aircraft without incurring the drag penalty of existing undermounted turret systems.